Foldable bridge structure



March 15, 1966 w. R. HIRE 3,239,862

FOLDABLE BRIDGE STRUCTURE Filed March 15, 1963 2 Sheets-Sheet 1 INVENTOR. 3.1 E E WILL/AM R. HIRE BY MAHONEY,MILLER & RAMBO ATTORNEYS.

March 15, 1966 w. R. HIRE FOLDABLE BRIDGE STRUCTURE 2 Sheets-Sheet 2 Filed March 13, 1963 INVENTOR. WILLIAM R. H/RE BY MAHONEY, MILLER & RAMBO ATTORNEYS.

United States Patent Ofiice 3,239,862 FULDABLE BRIDGE STRUCTURE William R. Hire, Newark, Ohio, assignor, by direct and mesne assignments, to Research Manufacturing, Inc., Newark, Ghio, a corporation of Ohio Filed Mar. 13, 1963, Ser. No. 264,927 4 Claims. (Cl. 141) This invention relates to a foldable bridge structure. It has to do, more particularly, with a bridge structure which is composed of a plurality of hingedly connected sections so arranged as to be folded or collapsed into a compact structure for storage or transportation or extended into straight, longitudinally-adjoining order for use as temporary bridge. The structure is particularly useful as a lightweight temporary foot bridge by contractors, combat troops, etc. since it can be folded readily, so as to occupy a minimum of space and be portable, and can be extended and locked readily in condition for use. It can also be used as a scaffold or platform board, or for other uses where an elongated load-supporting memher which can readily folded is desirable.

The primary object of this invention is to provide a bridge structure or the like which is structurally simple yet mechanically eflicient and which is so designed that it may be folded or collapsed easily into a compact arrangement for storage or transport or may be extended and rigidly locked into a straight, elongated support, with minimum effort and without the aid of detachable fastening devices, braces, etc. and without the aid of tools for applying or assembling such devices.

Another object of this invention is to provide a foldable bridge structure which is economical to fabricate but is sufficiently rugged to withstand normal usages, as a load-supporting bridge or the like.

This invention is disclosed hereinafter as being in the form of a lightweight foot bridge. However, it is to be understood that this is for illustrative purposes only and that it may be embodied in other forms as indicated above.

According to the present invention, the bridge frame is composed of a plurality of identically-formed, hingedlyconnected sections with successive sections being preferably hinged to one another along opposite faces thereof, so as to permit the sections to be folded one upon another successively in accordion style With the frame sections in substantially parallel, superimposed relationship to each other. Each of the hingedly-connected, frame-forming sections comprises a pair of opposed side rails and one or more deck-supporting tie members which extend transversely between the side rails and are joined therewith in a manner to permit relative rotation only of the side rails about their longitudinal axes. The hinge means for connecting adjacent side rails are so arranged that the lineal pintles or hinge axes thereof are disposed transversely of and in perpendicular relationship to the longitudinal axes of the side rails and the hinge means is turnable bodily with said side rails. Therefore, rotation of the connected side rails at both sides of the frame permits positioning of the hinge means thereof at a first unlocked position in which the hinge axes are disposed in parallel relationship to the common transverse plane of the longitudinal axes of the side rails at opposite side edges of the frame to permit said sections to be folded with respect to each other and a second locked position in which said hinge axes are disposed normal to said common plane to thereby lock said sections against relative folding movement. Each section of the frame will carry tread, deck or platform means suitable for supporting a person, vehicle, or other load which will be supported by the tie members so 3,239,862 Patented Mar. 15, 1966 that the side rails can be rotated relative to the deck or the like.

In the accompanying drawings, there is illustrated a preferred form of bridge structure embodying this invention.

In these drawings:

FIGURE 1 is a perspective view of the bridge structure is extended, locked condition, bridging a culvert.

FIGURE 2 is a side elevational view of the bridge structure in folded condition.

FIGURE 3 is a plan view of a portion of the bridge frame in extended, unlocked condition.

FIGURE 4 is a view similar to FIGURE 3 but showing the bridge frame in extended and locked condition.

FIGURE 5 is an enlarged, longitudinal sectional view taken through the bridge structure along the position indicated at line 55 of FIGURE 3.

FIGURE 6 is an enlarged, longitudinal sectional view taken at the position indicated by line 6-6 of FIGURE 4 through the bridge structure.

FIGURE 7 is an enlarged, transverse, sectional view taken along the position indicated at line 7-7 of FIG- URE 4 through the bridge frame.

FIGURE 8 is an enlarged detail of one of the frame hinge structures in transverse section taken along line 88 of FIGURE 4.

Wit-h reference to the drawings, the bridge structure embodying this invention is shown as comprising a plurality of practically identical sections 11, five of these sections being shown. However, it is to be understood that these sections may be varied in number as desired. The adjoining sections of the bridge are connected together by sets of hinges 12a with the sets of hinges. for connecting successive sections being located at opposite faces of the bridge frame so that the sections can be folded together in accordion style, as shown in FIGURE 2, wherein the sections are in flat, superimposed, substantially parallel relationship. When the bridge is unfolded or extended, the sections will be in longitudinallyadjoining reationship and have their side rails in a common longitudinal plane, as shown in FIGURES 1 and 3-6. All parts of the bridge are preferably made of lightweight material such as aluminum.

Each of the sections 11 comprises a pair of opposed, longitudinally-extending side rails 12 which may be of various cross section but are shown as being of I-beam form. These side rails are tied together in spaced relationship by one or more tie members or bars 13, two of these members for each section being shown, for example, and being shown as of box-like cross section. The opposite ends of the tie members or bars 13 are so connected to the side rails 12 that such rails can rotate relative to the tie members about their own axes. For this purpose, each side rail 12 has a pair of spaced channeled or spool-type bearings 14 formed integrally thereon at properly spaced longitudinal intervals. Each bearing is enclosed by a bearing yoke structure 15, one of which is at each end of each tie bar 13. Each yoke is composed of two separable parts having semi-circular sockets which are bolted together by the bolts 16 and 17, the bolt 17 also serving to connect the yoke structure to the associated end of the tie rod. The yoke does not grip the associated hearing but permits free rotation thereof. Thus, although the side rails 12 are held in spaced parallel relationship, they are free to rotate relative to the tie members about their own longitudinal axes.

The hinges 12a for connecting successive sections 11 are at opposite faces of the frame. Thus, each rail 12 of each section 11 is of standard form. and has at one end inwardly positioned hinge pintle-receiving lugs 20 and at the other end, outwardly positioned hinge pintlereceiving lugs 21. The lugs 20 of one section will interlit with the lugs 21 of an adjacent section and the openings therein will be aligned to receive the pintle pin 22. Thus, adjacent rails will be pivoted together in such a manner that the sections 11 can be folded into superimposed relationship in the manner indicated in FIGURE 2. However, they may be readily unfolded into aligning continuing relationship, as indicated in FIGURE 1. At this time, the adjacent hinged ends of the rails 12 will come into contact to limit further relative swinging movement. Thus, the bridge structure may be disposed across a space to be bridged without collapsing even though it is not yet locked.

The bridge structure may include any suitable form of decking 25 but in the example shown, it comprises a plurality of longitudinal strips secured to the tie members 13. These strips will be slightly shorter than the rails 12 and will be substantially flush with the outermost projecting portions of the hinge lugs 21 at one end of the section. However, other deck or tread surfaces may be provided. Furthermore, the deck strips or other deck members may be secured to the ties 13 by screws 26 or in any other suitable manner.

Assuming that the bridge is spanning the culvert, indicated in FIGURE 1, with the decking 25 uppermost, but that the frame is unlocked, as indicated in FIGURES 3 and 5, it issimple matter to lock the frame. It will be apparent that in unlocked condition the hinge pintles 22 of opposed side rails are opposite each other in transverse axial alignment and parallel to the common transverse plane of the longitudinal axes of the side rails at opposite sides of the frame. They are also parallel to the plane of the tie members 13 and the plane of the deck 25. However, successive transverse hinge axes will be at opposite sides of said common plane of the longitudinal axes of the side rails 12 since the pins 22 along each respective side rail are at opposite faces thereof. To lock the frame, to prevent folding, the aligning side rails at both sides of the frame are rotated as a unit relative to the ties 13, as indicated by the arrows in FIGURE 3, to positions indicated in FIGURES 4 and 6. All of the adjacent rail sections at each side of the frame are connected together for simultaneous rotation as a unit by the hinge means 12a. When the rails are rotated to the positions shown in FIGURES 4 and 6, the frame will be locked to prevent folding. At this time, the hinge axes on the side rails 12 at both sides of the frame will be inwardly of the rails and will be normal to the common plane of the longitudinal axes of the side rails as well as to the plane of the transverse tie members 13. In this locked condition, the bridge structure may be handled without folding or may be allowed to stay in bridging position where it will supports load applied thereto during usage.

To fold the bridge for storage or transportation, it is merely necessary to rotate the side rails 12 at each side of the bridge frame relative to the ties 13 back to the positions indicated in FIGURES 3 and 5. Then, since all the hinge pins 22 are disposed transversely of the frame, the sections 11 may be folded readily into the compact package shown in FIGURE 2.

According to the provisions of the patent statutes, the principles of this invention have been explained and have been illustrated and described in what is now considered to represent the best embodiment. However, it is to be understood that, within the scope of the appended claims, the invention may be practiced otherwise than as specifically illustrated and described.

Having thus described this invention, what is claimed is:

1. A bridge unit comprising a foldable frame composed of relatively adjoining frame sections, each of said sections including relatively spaced-apart, longitudinally extending load-supporting side rails and at least one loadsupporting tie member extending transversely between said rails, means rotatably connecting the side rails of each of said sections to the transversely-extending tie member to provide for axial turning movement only of said side rails about their longitudinal axes with respect to said tie member, hinge means connecting the side rails of one of said sections to the side rails of an adjoining section, said hinge means including hinge axes disposed at right angles to the longitudinal axes of said side rails, and said hinge means being turnably bodily with said side rails between a first position in which the hinge axes of opposed side rails are in axial alignment transversely and parallel to the common plane of the longitudinal axes of said side rails to permit said sections to be folded with respect to one another and a second position in which said hinge axes are disposed normal to said common plane to thereby lock said sections against relative folding movement, and load-supporting decking carried by each of said sections and terminating short of said hinge means means to permit relative folding of said sections.

2. A bridge unit according to claim 1 in which the side rails of successive sections at the respective sides of the frame are connected together by said hinge means for axial rotation as a unit, the hinge axes for connecting the respective side rail Sections being at opposite faces thereof.

3. A bridge unit according to claim 2 in which each section comprises a plurality of longitudinally-spaced tie members, said decking spanning the space between said tie members, being supported thereby and being secured thereto.

4. A bridge unit according to claim 3 in which each end of each tie member is provided with a bearing yoke which surrounds a bearing spool carried by the associated side rail.

References Cited by the Examiner UNITED STATES PATENTS 596,867 1/1898 Prick 14l 1,073,794 9/1913 Christensen l427 2,762,069 9/1956 Laycock 14l 3,043,109 7/1962 Erickson 14l X 3,081,840 3/1963 Hire 182l63 CHARLES E. OCONNELL, Primary Examiner.

JACOB L. NACKENOFF, Examiner, 

1. A BRIDGE UNIT COMPRISING A FOLDABLE FRAME COMPOSED OF RELATIVELY ADJOINING FRAME SECTIONS, EACH OF SAID SECTIONS INCLUDING RELATIVELY SPACED-APART, LONGITUDINALLY EXTENDING LOAD-SUPPORTING SIDE RAILS AND AT LEAST ONE LOADSUPPORTING TIE MEMBER EXTENDING TRANSVERSELY BETWEEN SAID RAILS, MEANS ROTATABLY CONNECTING THE SIDE RAILS OF EACH OF SAID SECTIONS TO THE TRANSVERSELY-EXTENDING TIE MEMBER TO PROVIDE FOR AXIAL TURNING MOVEMENT ONLY OF SAID SIDE RAILS ABOUT THEIR LONGITUDINAL AXES WITH RESPECT TO SAID TIE MEMBER, HINGE MEANS CONNECTING THE SIDE RAILS OF ONE OF SAID SECTIONS TO THE SIDE RAILS OF AN ADJOINING SECTION, SAID HINGE MEANS INCLUDING HINGE AXES DISPOSED AT RIGHT ANGLES TO THE LONGITUDINAL AXES OF SAID SIDE RAILS, AND SAID HINGE MEANS BEING TURNABLY BODILY WITH SAID SIDE RAILS BETWEEN A FIRST POSITION IN WHICH THE HINGE AXES OF OPPOSED SIDE RAILS ARE IN AXIAL ALIGNMENT TRANSVERSELY AND PARALLEL TO THE COMMON PLANE OF THE LONGITUDINAL AXES OF SAID SIDE RAILS TO PERMIT SAID SECTIONS TO BE FOLDED WITH RESPECT TO ONE ANOTHER AND A SECOND POSITION IN WHICH SAID HINGE AXES ARE DISPOSED NORMAL TO SAID COMMON PLANE TO THEREBY LOCK SAID SECTIONS AGAINST RELATIVE FOLDING MOVEMENT, AND LOAD-SUPPORTING DECKING CARRIED BY EACH OF SAID SECTIONS AND TERMINATING SHORT OF SAID HINGE MEANS MEANS TO PERMIT RELATIVE FOLDING OF SAID SECTIONS. 